Splunk Quick Reference Guide

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Quick Reference Guide
CONCEPTS
Overview
Index-time Processing: Splunk reads data from a source, such as a file or port, on a host (e.g. "my machine"), classifies that source into a sourcetype (e.g., "syslog", "access_combined", "apache_error", ...), then extracts timestamps, breaks up the source into individual events (e.g., log events, alerts, …), which can be a single-line or multiple lines, and writes each event into an index on disk, for later retrieval with a search. Search-time Processing: When a search starts, matching indexed events are retrieved from disk, fields (e.g., code=404, user=david,...) are extracted from the event's text, and the event is classified by matching against eventtype definitions (e.g., 'error', 'login', ...). The events returned from a search can then be powerfully transformed using Splunk's search language to generate reports that live on dashboards.

Eventtypes
Eventtypes are cross-referenced searches that categorize events at search time. For example, if you have defined an eventtype called "problem" that has a search definition of "error OR warn OR fatal OR fail", any time you do a search where a result contains error, warn, fatal, or fail, the event will have an eventtype field/value with eventtype=problem. So, for example, if you were searching for "login", the logins that had problems would get annotated with eventtype=problem. Eventtypes are essentially dynamic tags that get attached to an event if it matches the search definition of the eventtype.

Reports/Dashboards
Search results with formatting information (e.g., as a table or chart) are informally referred to as reports, and multiple reports can be placed on a common page, called a dashboard.

Apps

Go to splunkbase.com/apps to download apps

Apps are collections of Splunk configurations, objects, and code, allowing you to build different environments that sit on top of Splunk. You can have one app for troubleshooting email servers, one app for web analysis, and so on.

Events
An event is a single entry of data. In the context of log file, this is an event in a Web activity log: 173.26.34.223 - - [01/Jul/2009:12:05:27 -0700] "GET / trade/app?action=logout HTTP/1.1" 200 2953 More specifically, an event is a set of values associated with a timestamp. While many events are short and only take up a line or two, others can be long, such as a whole text document, a config file, or whole java stack trace. Splunk uses linebreaking rules to determine how it breaks these events up for display in the search results.

Permissions/Users/Roles
Saved Splunk objects, such as savedsearches, eventtypes, reports, and tags, enrich your data, making it easier to search and understand. These objects have permissions and can be kept private or shared with other users, via roles (e.g., "admin", "power", "user"). A role is a set of capabilities that you can define, like whether or not someone is allowed to add data or edit a report. Splunk with a Free License does not support user authentication.

Transactions
A transaction is a set of events grouped into one event for easier analysis. For example, given that a customer shopping at an online store would generate web access events with each click that each share a SessionID, it could be convenient to group all of his events together into one transaction. Grouped into one transaction event, it’s easier to generate statistics like how long shoppers shopped, how many items they bought, which shoppers bought items and then returned them, etc.

Sources/Sourcetypes
A source is the name of the file, stream, or other input from which a particular event originates – for example, /var/log/messages or UDP:514. Sources are classified into sourcetypes, which can either be well known, such as access_combined (HTTP Web server logs), or can be created on the fly by Splunk when it sees a source with data and formatting it hasn’t seen before. Events with the same sourcetype can come from different sources—events from the file /var/log/messages and from a syslog input on udp:514 can both have sourcetype=linux_syslog.

Forwarder/Indexer
A forwarder is a version of Splunk that allows you to send data to a central Splunk indexer or group of indexers. An indexer provides indexing capability for local and remote data.

Hosts
A host is the name of the physical or virtual device where an event originates. Host provides an easy way to find all data originating from a given device.

Indexes
When you add data to Splunk, Splunk processes it, breaking the data into individual events, timestamps them, and then stores them in an index, so that it can be later searched and analyzed. By default, data you feed to Splunk is stored in the "main" index, but you can create and specify other indexes for Splunk to use for different data inputs.

Fields
Fields are searchable name/value pairings in event data. As Splunk processes events at index time and search time, it automatically extracts fields. At index time, Splunk extracts a small set of default fields for each event, including host, source, and sourcetype. At search time, Splunk extracts what can be a wide range of fields from the event data, including user-defined patterns as well as obvious field name/value pairs such as user_id=jdoe.

Tags
Tags are aliases to field values. For example, if there are two host names that refer to the same computer, you could give both of those host values the same tag (e.g., "hall9000"), and then if you search for that tag (e.g., "hal9000"), Splunk will return events involving both host name values.

SEARCH LANGUAGE
A search is a series of commands and arguments, each chained together with "|" (pipe) character that takes the output of one command and feeds it into the next command on the right.

COMMON SEARCH COMMANDS
COMMAND chart/ timechart dedup DESCRIPTION
Returns results in a tabular output for (time-series) charting.

search-args | cmd1 cmd-args | cmd2 cmd-args | ...
Search commands are used to take indexed data and filter unwanted information, extract more information, calculate values, transform, and statistically analyze. The search results retrieved from the index can be thought of as a dynamically created table. Each search command redefines the shape of that table. Each indexed event is a row, with columns for each field value. Columns include basic information about the data as well as columns that are dynamically extracted at search-time. At the head of each search is an implied search-the-index-for-events command, which can be used to search for keywords (e.g., error), boolean expressions (e.g., (error OR failure) NOT success), phrases (e.g., "database error"), wildcards (e.g., fail* will match fail, fails, failure, etc.), field values (e.g., code=404), inequality (e.g., code!=404 or code>200), a field having any value or no value (e.g., code=* or NOT code=*). For example, the search:

Removes subsequent results that match a specified criterion.

eval Calculates an expression. (See EVAL FUNCTIONS table.) fields Removes fields from search results. head/tail lookup
Returns the first/last N results.

Adds field values from an external source.

sourcetype="access_combined" error | top 10 uri
will retrieve indexed access_combined events from disk that contain the term "error" (ANDs are implied between search terms), and then for those events, report the top 10 most common URI values.

rename Renames a specified field; wildcards can be used to specify
multiple fields.

replace rex

Replaces values of specified fields with a specified new value.

Subsearches
A subsearch is an argument to a command that runs its own search, returning those results to the parent command as the argument value. Subsearches are contained in square brackets. For example, finding all syslog events from the user that had the last login error:

Specifies regular expression named groups to extract fields.

search Filters results to those that match the search expression. sort
Sorts search results by the specified fields.

sourcetype=syslog [search login error | return user]
Note that the subsearch returns one user value, because by default the "return" command just returns one value, but there are options for more (e.g., | return 5 user).

stats Provides statistics, grouped optionally by fields. top/rare Displays the most/least common values of a field. transaction
Groups search results into transactions.

Relative Time Modifiers
Besides using the custom-time ranges in the user-interface, you can specify in your search the time ranges of retrieved events with the latest and earliest search modifiers. The relative times are specified with a string of characters that indicate amount of time (integer and unit) and, optionally, a "snap to" time unit:

[+|-]<time_integer><time_unit>@<snap_time_unit>
For example: "error earliest=-1d@d latest=-1h@h" will retrieve events containing "error" that occurred from yesterday (snapped to midnight) to the last hour (snapped to the hour). Time Units: specified as second (s), minute(m), hour(h), day(d), week(w), month(mon), quarter(q), year(y). "time_integer" defaults to 1 (e.g., "m" is the same as "1m"). Snapping: indicates the nearest or latest time to which your time amount rounds down. Snaps rounds down to the latest time not after the specified time. For example, if it is 11:59:00 and you "snap to" hours (@h), you will snap to 11:00 not 12:00. You can "snap to" a specific day of the week: use @w0 for Sunday, @w1 for Monday, etc.

Optimizing Searches
The key to fast searching is to limit the data that needs to be pulled off disk to an absolute minimum, and then to filter that data as early as possible in the search so that processing is done on the minimum data necessary. Partition data into separate indexes, if you’ll rarely perform searches across multiple types of data. For example, put web data in one index, and firewall data in another.

Community
ask questions, find answers. download apps, share yours.

• • • • • • • •

Search as specifically as you can (e.g. fatal_error, not *error*) Limit the time range to only what’s needed (e.g., -1h not -1w) Filter out unneeded fields as soon as possible in the search. Filter out results as soon as possible before calculations. For report generating searches, use the Advanced Charting view, and not the Flashtimeline view, which calculates timelines. On Flashtimeline, turn off ‘Discover Fields’ when not needed. Use summary indexes to pre-calculate commonly used values. Make sure your disk I/O is the fastest you have available.

splunkbase.com

SEARCH EXAMPLES
Filter Results
Filter results to only include those with "fail" in their raw text and status=0. Remove duplicates of results with the same host value. Keep only search results whose "_raw" field contains IP addresses in the nonroutable class A (10.0.0.0/8). … | search fail status=0 … | dedup host … | regex _raw="(?<!\d)10.\ d{1,3}\.\d{1,3}\.\d{1,3} (?!\d)" … | cluster t=0.9 showcount=true | sort limit=20 -cluster_count … | transaction host cookie maxspan=30s maxpause=5s

Add Fields
Set velocity to distance / time. Extract "from" and "to" fields using regular expressions. If a raw event contains "From: Susan To: David", then from=Susan and to=David. Save the running total of "count" in a field called "total_count". For each event where 'count' exists, compute the difference between count and its previous value and store the result in 'countdiff'. … | eval velocity=distance/ time … | rex field=_raw "From: (?<from>.*) To: (?<to>.*)" … | accum count as total_ count … | delta count as countdiff

Group Results
Cluster results together, sort by their "cluster_count" values, and then return the 20 largest clusters (in data size). Group results that have the same "host" and "cookie", occur within 30 seconds of each other, and do not have a pause greater than 5 seconds between each event into a transaction. Group results with the same IP address (clientip) and where the first result contains "signon", and the last result contains "purchase".

Filter Fields
Keep the "host" and "ip" fields, and display them in the order: "host", "ip". Remove the "host" and "ip" fields. … | transaction clientip startswith="signon" endswith="purchase" … | fields + host, ip … | fields - host, ip

Modify Fields
Rename the "_ip" field as "IPAddress". Change any host value that ends with "localhost" to "mylocalhost". … | rename _ip as IPAddress … | replace *localhost with mylocalhost in host

Order Results
Return the first 20 results. Reverse the order of a result set. Sort results by "ip" value (in ascending order) and then by "url" value (in descending order). Return the last 20 results (in reverse order). … | head 20 … | reverse … | sort ip, -url … | tail 20

Multi-Valued Fields
Combine the multiple values of the recipients field into a single value Separate the values of the "recipients" field into multiple field values, displaying the top recipients Create new results for each value of the multivalue field "recipients" For each result that is identical except for that RecordNumber, combine them, setting RecordNumber to be a multivalued field with all the varying values. Find the number of recipient values Find the first email address in the recipient field Find all recipient values that end in .net or .org Find the combination of the values of foo, "bar", and the values of baz Find the index of the first recipient value match "\.org$" … | nomv recipients … | makemv delim="," recipients | top recipients … | mvexpand recipients … | fields EventCode, Category, RecordNumber | mvcombine delim="," RecordNumber … | eval to_count = mvcount(recipients) … | eval recipient_first = mvindex(recipient,0) … | eval netorg_recipients = mvfilter(match(recipient, "\.net$") OR match(recipient, "\.org$")) … | eval newval = mvappend(foo, "bar", baz) … | eval orgindex = mvfind(recipient, "\.org$")

Reporting
Return events with uncommon values. Return the maximum "delay" by "size", where "size" is broken down into a maximum of 10 equal sized buckets. Return max(delay) for each value of foo split by the value of bar. Return max(delay) for each value of foo. Remove all outlying numerical values. Remove duplicates of results with the same "host" value and return the total count of the remaining results. Return the average for each hour, of any unique field that ends with the string "lay" (e.g., delay, xdelay, relay, etc). Calculate the average value of "CPU" each minute for each "host". Create a timechart of the count of from "web" sources by "host" Return the 20 most common values of the "url" field. Return the least common values of the "url" field. … | anomalousvalue action=filter pthresh=0.02 … | chart max(delay) by size bins=10 … | chart max(delay) over foo by bar … | chart max(delay) over foo … | outlier … | stats dc(host) … | stats avg(*lay) by date_ hour … | timechart span=1m avg(CPU) by host … | timechart count by host … | top limit=20 url … | rare url

Lookup Tables
Lookup the value of each event's 'user' field in the lookup table usertogroup, setting the event's 'group' field. Write the search results to the lookup file "users.csv". Read in the lookup file "users.csv" as search results. … | lookup usertogroup user output group … | outputlookup users.csv … | inputlookup users.csv

EVAL FUNCTIONS
FUNCTION

The eval command calculates an expression and puts the resulting value into a field (e.g. "...| eval force = mass * acceleration"). The following table lists the functions eval understands, in addition to basic arithmetic operators (+ - * / %), string concatenation (e.g., '...| eval name = last . ", " . last'), boolean operations (AND OR NOT XOR < > <= >= != = == LIKE).

DESCRIPTION
Returns the absolute value of X. Takes pairs of arguments X and Y, where X arguments are Boolean expressions that, when evaluated to TRUE, return the corresponding Y argument. Ceiling of a number X. Identifies IP addresses that belong to a particular subnet. Returns the first value that is not null. Evaluates an expression X using double precision floating point arithmetic. Returns eX. Returns the floor of a number X. If X evaluates to TRUE, the result is the second argument Y. If X evaluates to FALSE, the result evaluates to the third argument Z. Returns TRUE if X is Boolean. Returns TRUE if X is an integer. Returns TRUE if X is not NULL. Returns TRUE if X is NULL. Returns TRUE if X is a number. Returns TRUE if X is a string. This function returns the character length of a string X. Returns TRUE if and only if X is like the SQLite pattern in Y. Returns its natural log. Returns the log of the first argument X using the second argument Y as the base. Y defaults to 10. Returns the lowercase of X. Returns X with the characters in Y trimmed from the left side. Y defaults to spaces and tabs. Returns if X matches the regex pattern Y. Returns the max. Returns the MD5 hash of a string value X. Returns the min. Returns the number of values of X. Filters a multi-valued field based on the Boolean expression X. Returns a subset of the multivalued field X from start position (zerobased) Y to Z (optional). Given a multi-valued field X and string delimiter Y, and joins the individual values of X using Y. Returns the current time, represented in Unix time. This function takes no arguments and returns NULL. Given two arguments, fields X and Y, and returns the X if the arguments are different; returns NULL, otherwise. Returns the constant pi. Returns X .
Y

EXAMPLES
abs(number) case(error == 404, "Not found", error == 500,"Internal Server Error", error == 200, "OK") ceil(1.9) cidrmatch("123.132.32.0/25",ip) coalesce(null(), "Returned val", null()) exact(3.14*num) exp(3) floor(1.9) if(error==200, "OK", "Error") isbool(field) isint(field) isnotnull(field) isnull(field) isnum(field) isstr(field) len(field) like(field, "foo%") ln(bytes) log(number,2) lower(username) ltrim(" ZZZabcZZ ", " Z") match(field, "^\d{1,3}\.\d$") max(delay, mydelay) md5(field) min(delay, mydelay) mvcount(multifield) mvfilter(match(email, "net$")) mvindex( multifield, 2) mvjoin(foo, ";") now() null() nullif(fieldA, fieldB) pi() pow(2,10) random() relative_time(now(),"-1d@d") Returns date with the month and day numbers switched, so if the input was 1/12/2009 the return value would be 12/1/2009: replace(date, "^(\d{1,2})/ (\d{1,2})/", "\2/\1/") round(3.5) rtrim(" ZZZZabcZZ ", " Z")

abs(X) case(X,"Y",…) ceil(X) cidrmatch("X",Y) coalesce(X,…) exact(X) exp(X) floor(X)

isbool(X) isint(X) isnotnull(X) isnull(X) isnum(X) isstr() len(X) like(X,"Y") ln(X) log(X,Y) lower(X)

if(X,Y,Z)

ltrim(X,Y)

mvindex(X,Y,Z)

match(X,Y) max(X,…) md5(X) min(X,…) mvcount(X) mvfilter(X)

mvjoin(X,Y)

pi() pow(X,Y) random() relative_time (X,Y) replace(X,Y,Z) round(X,Y) rtrim(X,Y)

nullif(X,Y)

now() null()

Returns a pseudo-random number ranging from 0 to 2147483647. Given epochtime time X and relative time specifier Y, returns the epochtime value of Y applied to X. Returns a string formed by substituting string Z for every occurrence of regex string Y in string X. Returns X rounded to the amount of decimal places specified by Y. The default is to round to an integer. Returns X with the characters in Y trimmed from the right side. If Y is not specified, spaces and tabs are trimmed.

EVAL FUNCTIONS (continued)
FUNCTION DESCRIPTION
Returns true if the event matches the search string X. Returns X as a multi-valued field, split be delimiter Y. Returns the square root of X. Returns epochtime value X rendered using the format specified by Y. Given a time represented by a string X, returns value parsed from format Y. Returns a substring field X from start position (1-based) Y for Z (optional) characters. Returns the wall-clock time with microsecond resolution. Converts input string X to a number, where Y (optional, defaults to 10) defines the base of the number to convert to. Returns a field value of X as a string. If the value of X is a number, it reformats it as a string; if a Boolean value, either "True" or "False". If X is a number, the second argument Y is optional and can either be "hex" (convert X to hexadecimal), "commas" (formats X with commas and 2 decimal places), or "duration" (converts seconds X to readable time format HH:MM:SS). Returns X with the characters in Y trimmed from both sides. If Y is not specified, spaces and tabs are trimmed. Returns a string representation of its type. Returns the uppercase of X. Returns the URL X decoded. Given pairs of arguments, Boolean expressions X and strings Y, returns the string Y corresponding to the first expression X that evaluates to False and defaults to NULL if all are True.

EXAMPLES
searchmatch("foo AND bar") split(foo, ";") sqrt(9) strftime(_time, "%H:%M") strptime(timeStr, "%H:%M") substr("string", 1, 3) +substr("string", -3) time() tonumber("0A4",16) This example returns: foo=615 and foo2=00:10:15: … | eval foo=615 | eval foo2 = tostring(foo, "duration") trim(" ZZZZabcZZ ", " Z") This example returns: "NumberStringBoolInvalid": typeof(12)+ typeof("string")+ typeof(1==2)+ typeof(badfield) upper(username) urldecode("http%3A%2F%2Fwww.splunk. com%2Fdownload%3Fr%3Dheader") validate(isint(port), "ERROR: Port is not an integer", port >= 1 AND port <= 65535, "ERROR: Port is out of range")

searchmatch(X) split(X,"Y") sqrt(X) strftime(X,Y) strptime(X,Y) substr(X,Y,Z) tonumber(X,Y) tostring(X,Y) trim(X,Y) typeof(X) upper(X) urldecode(X) validate(X,Y,…)

time()

COMMON STATS FUNCTIONS
FUNCTION DESCRIPTION

Common statistical functions used with the chart, stats, and timechart commands. Field names can be wildcarded, so avg(*delay) might calculate the average of the delay and xdelay fields.

count(X)

avg(X) dc(X)

Returns the average of the values of field X. Returns the number of occurrences of the field X. To indicate a specific field value to match, format X as eval(field="value"). Returns the count of distinct values of the field X. Returns the first seen value of the field X. In general, the first seen value of the field is the chronologically most recent instance of field. Returns the last seen value of the field X. Returns the list of all values of the field X as a multi-value entry. The order of the values reflects the order of input events. Returns the maximum value of the field X. If the values of X are non-numeric, the max is found from lexicographic ordering. Returns the middle-most value of the field X. Returns the minimum value of the field X. If the values of X are non-numeric, the min is found from lexicographic ordering. Returns the most frequent value of the field X. Returns the X-th percentile value of the field Y. For example, perc5(total) returns the 5th percentile value of a field "total". Returns the difference between the max and min values of the field X. Returns the sample standard deviation of the field X. Returns the population standard deviation of the field X. Returns the sum of the values of the field X. Returns the sum of the squares of the values of the field X. Returns the list of all distinct values of the field X as a multi-value entry. The order of the values is lexicographical. Returns the sample variance of the field X.

first(X) last(X) list(X) median(X)

max(X) min(X)

perc<X>(Y)

mode(X)

range(X) stdev(X) sum(X)

stdevp(X)

values(X)

sumsq(X)

var(X)

REGULAR EXPRESSIONS (REGEXES)
REGEX \s \S \d \D \w \W [...] * + ? | (?P<var> ...) (?: ... ) ^ $ \ NOTE
white space not white space digit not digit word character (letter, number, or _ ) not a word character any included character no included character zero or more one or more zero or one or named extraction logical grouping start of line end of line number of repetitions escape lookahead negative lookahead

Regular Expressions are useful in multiple areas: search commands regex and rex; eval functions match() and replace(); and in field extraction.

EXAMPLE \d\s\d \d\S\d \D\D\D \w\w\w \W\W\W [^xyx] \w* \d+ [a-z0-9#] \d\d\d-\d\d-\d\d\d\d

EXPLANATION
digit space digit digit non-whitespace digit SSN three non-digits three word chars three non-word chars any char that is a thru z, 0 thru 9, or # any char but x, y, or z zero or more words chars integer SSN with dashes being optional word or digit character pull out a SSN and assign to 'ssn' field word-char then digit OR digit then word-char line begins with at least one digit line ends with at least one digit between 3-5 digits escape the [ char "error" must be preceded by a non-digit "error" cannot be preceded by a digit

[^...]

\d\d\d-?\d\d-?\d\d\d\d \w|\d (?P<ssn>\d\d\d-\d\d\-\d\d\d\d) (?:\w|\d)|(?:\d|\w) ^\d+ \d+$ \[

{...} (?= ...) (?! ...)

\d{3,5} (?=\D)error (?!\d)error

COMMON SPLUNK STRPTIME FORMATS
%H %I %M %S %N %p %Z %s %d %j %w %a %A

strptime formats are useful for eval functions strftime() and strptime(), and for timestamping of event data. 24 hour (leading zeros) (00 to 23) 12 hour (leading zeros) (01 to 12) Minute (00 to 59) Second (00 to 61) subseconds with width (%3N = millisecs, %6N = microsecs, %9N = nanosecs) AM or PM Time zone (GMT) Seconds since 1/1/1970 (1308677092) Day of month (leading zeros) (01 to 31) Day of year (001 to 366) Weekday (0 to 6) Abbreviated weekday (Sun) Weekday (Sunday) Abbreviated month name (Jan) Month name (January) Month number (01 to 12) Year without century (00 to 99) Year (2008) 1998-12-31 98-12-31 Jan 24, 2003 January 24, 2003 q|25 Feb '03 = 2003-02-25|
Copyright © 2011 Splunk Inc. All rights reserved.

Time

Days

Months

%b %B %m

Years

Examples

%Y-%m-%d %y-%m-%d %b %d, %Y %B %d, %Y q|%d %b '%y = %Y-%m-%d|

%y %Y

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